Use toLowerCase() and toUpperCase() with Locale.ENGLISH

This commit updates all `toLowerCase()` and `toUpperCase` invocations to
use the variant that takes a `Locale` to avoid locale-specific side
effect.

Closes gh-12213

spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/boot/configurationmetadata/JsonReader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,7 @@ import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Locale;
 
 import org.json.JSONArray;
 import org.json.JSONObject;
@@ -183,7 +184,7 @@ class JsonReader {
 	private Deprecation.Level parseDeprecationLevel(String value) {
 		if (value != null) {
 			try {
-				return Deprecation.Level.valueOf(value.toUpperCase());
+				return Deprecation.Level.valueOf(value.toUpperCase(Locale.ENGLISH));
 			}
 			catch (IllegalArgumentException e) {
 				// let's use the default

spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/metadata/ConfigurationMetadata.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,7 @@ import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.ListIterator;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 
@@ -197,7 +198,7 @@ public class ConfigurationMetadata {
 			previous = current;
 
 		}
-		return dashed.toString().toLowerCase();
+		return dashed.toString().toLowerCase(Locale.ENGLISH);
 	}
 
 	private static <T extends Comparable<T>> List<T> flattenValues(Map<?, List<T>> map) {

spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Layouts.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,7 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 
@@ -45,13 +46,14 @@ public final class Layouts {
 		if (file == null) {
 			throw new IllegalArgumentException("File must not be null");
 		}
-		if (file.getName().toLowerCase().endsWith(".jar")) {
+		if (file.getName().toLowerCase(Locale.ENGLISH).endsWith(".jar")) {
 			return new Jar();
 		}
-		if (file.getName().toLowerCase().endsWith(".war")) {
+		if (file.getName().toLowerCase(Locale.ENGLISH).endsWith(".war")) {
 			return new War();
 		}
-		if (file.isDirectory() || file.getName().toLowerCase().endsWith(".zip")) {
+		if (file.isDirectory()
+				|| file.getName().toLowerCase(Locale.ENGLISH).endsWith(".zip")) {
 			return new Expanded();
 		}
 		throw new IllegalStateException("Unable to deduce layout for '" + file + "'");

spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/RunProcess.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,7 @@ import java.io.InputStreamReader;
 import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Locale;
 
 import org.springframework.util.ReflectionUtils;
 
@@ -128,7 +129,8 @@ public class RunProcess {
 	// There's a bug in the Windows VM (https://bugs.openjdk.java.net/browse/JDK-8023130)
 	// that means we need to avoid inheritIO
 	private static boolean isInheritIOBroken() {
-		if (!System.getProperty("os.name", "none").toLowerCase().contains("windows")) {
+		if (!System.getProperty("os.name", "none").toLowerCase(Locale.ENGLISH)
+				.contains("windows")) {
 			return false;
 		}
 		String runtime = System.getProperty("java.runtime.version");

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/PropertiesLauncher.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,6 +27,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Properties;
 import java.util.Set;
 import java.util.jar.Manifest;
@@ -489,7 +490,7 @@ public class PropertiesLauncher extends Launcher {
 	}
 
 	private Archive getArchive(File file) throws IOException {
-		String name = file.getName().toLowerCase();
+		String name = file.getName().toLowerCase(Locale.ENGLISH);
 		if (name.endsWith(".jar") || name.endsWith(".zip")) {
 			return new JarFileArchive(file);
 		}
@@ -566,7 +567,8 @@ public class PropertiesLauncher extends Launcher {
 		if (path.startsWith("./")) {
 			path = path.substring(2);
 		}
-		if (path.toLowerCase().endsWith(".jar") || path.toLowerCase().endsWith(".zip")) {
+		String lowercasePath = path.toLowerCase(Locale.ENGLISH);
+		if (lowercasePath.endsWith(".jar") || lowercasePath.endsWith(".zip")) {
 			return path;
 		}
 		if (path.endsWith("/*")) {

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/util/SystemPropertyUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 package org.springframework.boot.loader.util;
 
 import java.util.HashSet;
+import java.util.Locale;
 import java.util.Properties;
 import java.util.Set;
 
@@ -188,7 +189,8 @@ public abstract class SystemPropertyUtils {
 			}
 			if (propVal == null) {
 				// Try uppercase with underscores as well.
-				propVal = System.getenv(key.toUpperCase().replace('.', '_'));
+				propVal = System.getenv(key.toUpperCase(Locale.ENGLISH)
+						.replace('.', '_'));
 			}
 			if (propVal != null) {
 				return propVal;